Recent content by josdavi

  1. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Order 2 Icosahedron Puzzle I forgot to indicate that if we put 12 Simplex Stars onto the 12 concaved parts of the Ball-Shaped object formed by 20 octahedrons connected together, then it will become a larger (order 2) Regular Icosahedron. we can obviously see the larger Regular Icosahedron...
  2. J

    How to interpret 3^3 + 4^3 + 5^3 = 6^3 ?

    I found a special equation about 29 years ago (with a FORTRAN Program) - 3**3 + 4**3 + 5**3 = 6**3 I was/am not a mathematician, not able to fully understand the meaning behind this equation, maybe someone can derive some useful ideas like Pythagoras' theorem. Is this equation related to...
  3. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Thank Hurkyl. I have to tell you why I think a regular icosahedron is 20 regular tetrahedrons being put together. There is a long story, I sumarize it as short as possible. (1). A regular Icosahedron has 20 faces that are equilateral triangles. A regular tetrahedron has 4 faces that are...
  4. J

    Proving Axioms: An Explanation

    I know that a theorem can be deduced from the AXIOMS of a formal system, but I do not know how to prove an axiom. Would you please teach me ? How to prove an axiom ? How did the axiomatic rules become axiom ? I think some statements or formulas are axiomatic, although they seem...
  5. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Thank Hurkyl again. I just visited a website having many useful information. http://www.intent.com/sg/polyhedra.html There is a Table of Platonic And Archimedean Solids (Updated: Wed, 26 Mar 2003.) I got some values as below - Platonic Icosahedron total surface area (when edge...
  6. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Thank bogdan. Have you tried to glue 20 regular tetrahedron models to form the regular icosahedron shape ? I did so, and it is definitely possible. I found the relationship between s and R (of previous question) is R = s or The circumdiameter of the regular icosahedron is two...
  7. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Thank Hurkyl. But if we pack five Regular Tetrahedron pieces together, surely we can get a Pentagonal-like structure. I do not know its formal name, therefore I just called it Simplex Star. A Simplex Star formed by 5 regular tetrahedrons, has 7 vertices, 10 faces and 15 edges. Five of the...
  8. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Thank marcus. I am not a mathematician, so I really need the teaching. I had visited askgeeve.com a few days ago, this site gave me many formulas of the volumes of Polyhedras, but I could not understand them. I am mostly interested to confirm my assumption - A Regular Icosahedron can be made...
  9. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Please teach me. Is one Regular Icosahedron equal to twenty Regular Tetrahedrons ? If the edgelength of both Regular Polyhedras is 1, What would be their volumes ? Can we prove (or disprove) the equation below ? volume of Regular Icosahedron = 20 * volume of Regular Tetrahedron...
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